A battery (secondary battery) is degraded at a speed corresponding to a usage environment. With degradation, a charge amount at the time of full charge (hereinafter, referred to as “full charge capacity” as appropriate) decreases and a discharge characteristic is reduced. If a battery mounted in a vehicle is degraded, traveling performance is reduced. Thus, it is desirable to estimate a period (remaining life) during which the battery can exhibit predetermined performance. In a technique described in JP2007-195312A, a remaining life is predicted by estimating a degradation degree of a battery in association with a square root of a total traveling distance.